1. Field of the Invention
This invention pertains to phosphor application for high power LED devices used in lighting products. More particularly, the invention relates to a lighting product incorporating an LED lamp and a phosphor layer pre-applied to a plastic or glass cap or housing integral to the LED lamp structure.
2. Discussion of the Art
Current state of the art light emitting diode (LED) technology is less than 10 percent efficient in the visible spectra. The LED lamps of the GaN (gallium nitride) technology create white light by the conversion of blue or UV spectral emissions using phosphors and dyes to convert light into the white spectra.
The light output for a single LED is below that of known incandescent lamps, which are approximately 30 percent efficient in the visible spectra. Flashlights, using incandescent bulbs, have approximately 20 lumens of light output. An LED device having a comparable light output power density necessitates a larger LED design or a design comprising a multiple LED configuration. The structure must then be electrically pumped or driven at two to four times in rated current, to create an equivalent light output, as compared to conventional filament bulb technologies.
Presently available GaN technology disposes phosphor on the individual GaN die and converts the blue or UV light to a white light at the die surface. This die configuration is problematic in that it is difficult to mass produce. Moreover, the resultant LED lamps generally have varying color and light output attributes. In this regard, an identical phosphor material typically yields radically different color and/or light output depending on the thickness of the phosphor at the edges and top of the GaN die, which varies according to application techniques.
Thus, there is a particular need for both an improved LED lamp structure having a GaN LED die and process for application of a phosphor to the GaN LED die that results in both uniform color and light output.
A new and improved high power lamp structure including a white LED device having an integrated pre-phosphorized bulb or lens structure is provided. Briefly, in accordance with one embodiment of the present invention, a high power LED lamp structure is provided which comprises at least one LED die and at least one lensing structure, at least one side of the at least one lensing structure having a phosphor layer applied thereto. The lensing structure is positioned in the LED lamp structure so that emitted light from the LED die excites the phosphor layer applied to the lensing structure.
A principal advantage of the present invention is that an integrated pre-phosphorized bulb or lens structure is disclosed, which replaces the application of phosphor layer to a GaN die surface.
A second advantage of the present invention is that an LED appliance is disclosed that yields equivalent energy on a surface when compared to a conventional filament incandescent bulb (including halogen technologies).
A third advantage of the present invention is that the phosphor layer, which is temperature sensitive and has an efficiency that degrades with temperature, is positioned in the lamp structure in a more controlled and lower temperature area of the lamp structure.
Still another advantage of the present invention is that a novel LED lamp structure is disclosed which can be mass produced.
Still a further advantage of the present invention is that an LED lamp structure is disclosed having longer lamp life, long battery life, and increased resistance to breakage of the bulb when the flashlight is dropped.
Still another advantage of the present invention is that a low cost assembly lighting product is disclosed for high volume appliance construction, particularly for flashlights of the hand-held variety.
Still another advantage of the present invention is an LED equivalent to a conventional incandescent bulb, is disclosed for use in connection with the upgrade or retrofit of flashlight devices or the like as a structural enhancement.
Still a further advantage of the present invention is that an enhanced bulb and lensing structure yielding good light flux area as compared to a conventional incandescent bulb flashlight is disclosed for use in the mass production of a flashlight design.